Step 2: We have a formula for calculating the average slope of a function that is: A = (f(x) âf(a)) /(x â a), 'A' represents the average slope. Here (x-a) is used to represent the change in input values and f(x) â f(a) is used to denote the change in output of the function f(x).
This value is expressed in hours and represents the number of hours before the lamp is at half its original brightness. The expected life of a lamp will vary based on the lamp technology and the projector; however, most projectors offer about 2000 hours. The lamp's success rate is based on a bell curve, so that a majority of (but not all) lamps will meet the lamp life hours specified.
While extended lamp life is a plus, don't let lamp life itself be an overly huge factor in selecting a projector. Certainly a longer lamp life can mean lower cost of ownership. However, if you get 2,000 hours out of a lamp it will deliver 1,000 two-hour movies. If the replacement lamp is $400, that is about forty cents a movie. If you watch thirty movies a month, your lamp cost is about $12 per monthâthe cost of a medium Domino's pizza. Compared to the cost of renting or buying those thirty DVDs a month, the lamp cost is almost invisible.